Method and apparatus for the largescale production of snow fields for sports use



June 28, 1966 J. BROCOFF ET AL METHOD AND APPARATUS FOR THE LARGE-SCALE PRODUCTION OF SNOW FIELDS FOR SPORTS USE 2 Sheets-Sheet 1 Filed July 10, 1964 FIG.

FIG. 5.

FIG. 3

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C) Air Blower INVENTORS J0 ck Brocoff Harry K. Orbach Robert J. Sunder/and BY W ATTORNEY June 28, P366 J. BROCOFF ET AL METHOD AND APPARATUS FOR THE LARGE-SCALE PRODUCTION OF SNOW FIELDS FOR SPORTS USE 2 Sheets-Sheet 2 Filed July 10, 1964 United States Patent METHDD AND 1%?PARATUS FOR THE LARGE- SQALE PRODUCTIDN 0F SNOW FIELDS FOR SMNRTS USE Jack Brocoft, Fullerton, Harry K. Orbach, Corona del Mar, and Robert J. Sunderland, Glendora, Calif., assignors to Conch international Methane Limited, Nassau, Bahamas, a company of the Bahamas Filed July 10, 1964, Ser. No. 381,712 14 Claims. (Cl. 6257) This invention relates to a method and apparatus for producing a snow field, especially in a warm climate, of sufiicient extent to be useful for outdoor winter-type sports such as skiing, tobogganing, and so forth.

It is a primary object of the invention to produce a snow field of sufiicient extent and thickness to be useful outdoors even in a warm climate having a temperature well above the freezing point of water, which can be operated on an economically feasible commercial basis for sports and similar use.

The interest in winter sports keeps increasing every year. Unfortunately, most natural ski areas are remote from population centers and have favorable snow'conditions for only a few months out of the year. Quite often, even during those months when snow is expected, the weather may be such that there is no snow with consequent loss of revenue to hotel owners, ski-lift operators, etc. The present invention proposes to make and distribute snow economically over a large area independently of the prevailing atmospheric conditions, so that any conveniently located area can be used for skiing, tobogganing, or other winter snow sports. It is a primary object of the invention to provide a system for doing this which is economically feasible for operation on a commercial basis.

The invention contemplates the use of artifical refrigeration to convert water into snow in a controlled atmosphere maintained below the freezing point of water, and using compressed chilled air or other suitable gas to immediately convey the snow through a duct and to distribute it over the desired area. It is an important feature of the invention that the snow is at all times, until it is distributed on the ground, maintained well below the freezing point of water, whereby it can be conveyed as a dry powder from the point of origin to the point of use. According to the invention, a closed gas circuit is used to furnish the freezing atmosphere for converting the water into snow, the gas being continually recirculated through the enclosed space, except for some which is diverted to convey the snow through a duct to the point of use, the amount of air which is thus removed being made up by supplying'make-up directly to the enclosed space so as to avoid the necessity of drying the air.

Another feature of the invention lies in the collection and reuse of the melted runoff from the snow field to provide at least some of the water which is used in making the snow, in order to conserve refrigeration by utilizing the relatively low temperature of the run-off water.

Snow-making systems are known, as shown in Patent No. 2,646,471, for converting water into snow directly at the point of use for skiing, and so forth, but these are suitable only for use in low temperature situations under approximately normal winter conditions, and they are entirely impractical for use in situations where the normal ambient temperature is well above the freezing point of water.

The specific nature of our invention as well as other objects and advantages thereof will clearly app-ear from a description of a preferred embodiment as shown in the accompanyingdrawings, in which:

FIG. 1 is a schematic perspective representation of a snow field area according to the invention, illustrating the manner in which the snow is produced and applied to the area;

FIG. 2 is a flow sheet showing a typical system for the production of snow according to the invention;

FIG. 3 is a schematic sectional view through a snow tower for converting water into snow, and for conducting the dry snow into a duct for use;

FIG. 4 is a flow sheet of a modification using a liquid refrigerant such as CO for direct cooling and freezing of the water; and

FIG. 5 is a sketch of the air cooler.

Referring to FIG. 1, the snow field area 2 is preferably laid on a slope, constituted by the side of a hill 3 which may be either natural or artificially made for the purpose. Since the top of the ski or toboggan run should be at a good elevation, it will be assumed that the hill is in the order of 1500 feet high, and the slope should be well over a half mile in length if possible, although of course these dimensions can be varied in accordance with local conditions and available surfaces. The skiing area 2 is surrounded by a header or duct 4 for conveying the dry snow, as will be described below. This header may be laid directly upon the ground, may be elevated above the ground, or may be buried below the ground except for the feeder ducts 6 through which the snow is applied to the field 2. Feeder ducts 6 are suitably spaced along the header 4, and are provided with suitable valves 7 and hose connections 8 whereby a hose line 9 having a suitable nozzle 11 may be attached, it being understood that any suitable number of such hose lines may be employed. Inthis manner, the snow issuing through nozzles 11 may be manually distributed over the area of use 2, in order to build up the thickness of the snow to the desired degree. Since the installation is typically intended for use in an area in which the temperature is well above the melting point of snow, it will be understood that the snow must be continually replenished, which is preferably done in the evening, and the melted run off is collected in any suitable manner, schematically indicated by channels 12, into a return pipe 13, and fiow back, preferably by gravity, into reservoir 15 for reuse in making snow as will be described below. This particular system is designed to make approximately 296,000 lbsz/hr. of snow. It is described by way of example only. The flow rates and sizes of equipment will vary with the snowmaking capacity desired. Pressures and temperatures may also vary to achieve optimum economy depending on local conditions, power costs, size of installation, and so forth.

Snow for the system is made in snow tower 16 as will be described below, and passes from the snow tower into duct 14, which is supplied with cold air from blower 17 under a low positive pressure, e.g., 5 pounds gauge, to convey the snow through the header 4. The snow is made by freezing water droplets which are conducted to the snow tower via pipe 18 and pump 19 from water reservoir 15. When the system is in continuous operation, most of the water in the reservoir 15 will be runoff water from return pipe 13 as previously described.

The snow making tower 16 is an insulated tower typically feet in diameter by some 40 feet high. The tower may be steel, aluminum, concrete, or other suitable construction material. The atmosphere in this chamber is maintained at 0 F. by a circulating air system. As best seen in FIGS. 2 and 3, the air enters on line 21 at a temperature of approximately l00 F., and leaves the chamber on line 22 at a temperature of approximately 0 F., having been warmed to this temperature by the water which has been converted into snow. The air in line 22 passes through a filter 23 to remove entrained snow, and continues on line 24 to blower 26, which boosts the pressure from atmospheric to approximately 0.3 p.s.i.g. so as to overcome the pressure drop in the system. From the pump 26, the air is cooled to 100 F. by evaporating liquid natural gas. The air cooler is similar to the type where atmospheric air is used as the cooling medium, except that in this application the device is used to cool the atmospheric air. Each exchanger 28, 28a is designed for the total heat load in order to allow one exchanger to be taken out of service for deriming. A mixture of precooled air and water in line 18 is sprayed into tower 16, as best shown in FIG. 3, and this is cooled by the air from line 21 in counter-current flow, although co-current flow is also useful under some conditions, to produce a snow which falls to the bottom portion of tower 16, and is removed through a rotary valve 28 which operates somewhat on the principle of a revolving door to pass the snow into duct 14 where the pressure is higher than that in chamber 16, but without allowing air from duct 14 at the higher pressure to pass through to the interior of chamber 16. The higher pressure in duct 14 is, as previously explained, necessary for conveyance of the snow through the header system. 4. The pressure for this purpose is provided by pump 17, which is supplied from line 27 with air at F.

The water in line 18 is supplied'by high pressure pump 19, which must overcome the elevation head, assumed to be 1500 feet, and also must supply the pressure required for pipe friction, heat exchanger pressure drop, and atomizing pressure drop through the snow nozzles. In the system shown, methanol is used as an auxiliary cooling fluid in line 31 to prevent freeze-ups in the water chiller 32. The methanol is supplied from. surge tank 33 through pump 34 to line 31. It is cooled to the required low temperature (e.g., 0 F.) by heat exchange in exchanger 36 with the primary coolant, which may be liquid natural gas (LNG), liquid CO or other suitable coolant. This coolant is supplied from tank 37 through pump 38 to line 39, thence through line 41 or 41a to heat exchanger 28 or 28a as previously described, for cooling the air from line 27 down to a temperature of l00 F. in line 21. The cool-ant then passes through a line 43 to the methanol-LNG heat exchanger 36, and through line 44 to atomizing air precooler 46, for precooling the air on line 47 from its initial temperature of 90 F. down to 40 F. in line 48, from which the atomizing air is mixed with water in line 49 to supply the atomizing spray heads 51 shown in FIG. 3. The fine spray thus produced consists of atomized water particles having a large area relative to their individual masses, whereby they are rapidly frozen by the cold air from line 21 to produce the desired snow. It will be understood that the term snow includes any discrete granular frozen water particles suitable for a skiing or tobogganing surface. If desired, hydraulic atomization can be use-d, which requires a special nozzle and the use of higher pressure than is required for gas atomization.

The liquid coolant in lines 43 and 44, after passing through heat exchangers 36, 46, respectively merge again in line 51, from which the coolant is taken for any suitable use. In the case of LNG, this material is now in gaseous form and may suitably be used as a fuel. The atomizing air in line 47 is obtained from the atmosphere via compressor 52 and a heat exchanger, which may be a water cooler, which reduces its temperature subsequent to the pumping operation to 90 F.

It will be noted that the air in line 14 is removed from the circulating system which includes the cooling tower 16, lines 22, 24, 27 and 21. It is therefore necessary to make up this amount of air, and this make-up air is supplied by pump 56 from atmospheric air. Since atmospheric air ordinarily contains a substantial amount of moisture, it is necessary to ensure that this air is in dry condition in the above-described circulating air system. It is therefore a feature of the invention that air from compressor 56 is introduced on line 57 at the bottom of tower 16, whereby its moistureis added to the moisture from the atomizing spray heads, to aid in the production of snow, while the make-up air is dried by this action, and therefore passes into line 22 as dry air. This avoids the necessity for a separate air drier.

As shown in FIG. 3, the cooling tower 16 is preferably provided with an insulating jacket 58, and it will be understood that the duct 14, header 4, and all of the cold air lines of the system are similarly insulated in accordance with good practice.

While the system shown above is effective where LNG or a similar liquid gas is available as the primary coolant, the system can also be operated with conventional compression refrigeration as the primary cooling means, and can alternatively be operated with liquid CO where this is available, supplied directly into line 21 in lieu of the cooling system shown. In this case, the liquid CO is converted into a gas in the process of snow production, and passes in gaseous form through line 22, and thence either into the atmosphere or for any other suitable use.

The operating temperatures and pressures shown in FIG. 2 are by way of example only, and are intended to indicate typical ranges for use in a practical system. The system shown is intended to produce sufficient snow over an area in the order of 500 feet Wide and at least a half mile long, to accommodate a snow melt rate of four to five inches per day, which will enable the system to be used outdoors even in a normally mild climate.

In initially starting this system, the header 4 should be pre-cooled before snow is sent through the line, in order to avoid the possibility of snow melting in the line and clogging the system. This can be done by passing air from blower 17 through line 14 and through the header at 0 F., but without any snow, for a sufiicient time to cool the entire header system down well below the freezing point.

FIG. 4 shows an alternative system using liquid CO initially stored in tank 61, and passed through pump 62 and line 63 to water pre-cooler 64 for precooling water from pump 19 to a temperature .of 40 F. in line 49, from which it is supplied to the spray nozzles 51', the gas atomization being provided by C0 gas in line 48'. CO gas is also passed on line 65, through valve 66 which is controlled by a suitable automatic flow controller 67, and into the snow tower 16'. Here the CO expands and rises counter-current to the atomized water, freezing it into the desired snow form. If desired, co-current flow may also be used as previously explained. The warm CO can be vented into the atmosphere through line 69 or could, alternatively, be compressed, cooled and liquefied in the conventional refrigeration cycle and returned to tank 61.

The partially vaporized CO from exchanger 64 is split into two streams 48 and 71, the stream in line 48' being used, as previously described, to atomize the water in a suitable spray nozzle, and the CO in line 71, under control of valve 72 and automatic pressure control 73, being used to furnish the conveying gas medium for the snow in line 6.

A warm bypass line 74 is shown in this example to keep the CO from forming a solid on expansions through valve 67 and plugging the line. The falling water, after freezing into snow, is fed into the tower by a suitable means such as star valve 28 previously described, which prevents the snow from being blown back into the tower. Alternatively, the tower can be operated at higher pressure than the pipe line 6, although this would necessitate a more expensive tower.

The water particle size required to form a satisfactory snow will vary with the operating conditions in general, but the particle size should be controlled so that the particles are fine enough, causing a snow or snow-like substance to be formed. Although a fairly skiable snow can be made by crushing ice, it is preferable to produce a snow as nearly as possible similar to natural snow, both because this provides a superior skiing surface, and also 5 because of its superior insulating qualities, which tends to reduce the melting rate.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of our invention as defined in the appended claims.

We claim:

1. Method of making and distributing snow for sports use at above-freezing temperatures, which comprises (a) making artificial snow in a controlled chamber in an atmosphere maintained below the freezing point of water,

(b) passing snow from said chamber into a duct,

(c) conveying the snow through said duct by entraining it in chilled air under pressure and at a temperature below the melting point of the snow, and causing said air to move along the duct,

(d) distributing the snow from the duct to a remote point of use.

2. Method as recited in claim 1, including the further step of recovering the melted snow, from the point of use, in the form of cold water, and using this Water to make more'snow in step (a) of the preceding claim.

3. A method of making an artificial snowfield for sports use comprising the following steps:

(a) making artificial snow in an enclosed chamber by atomizing feed water and bringing the atomized water particles into contact with chilled air at a below-freezing temperature,

(b) distributing the snow from the chamber to an area of use which is at a temperature above the melting point of the snow, whereby the snow melts during use into run-off water,

(c) collecting the cold run-off water at the site of use of the snow, and conveying it back while at a low temperature to said enclosed chamber for re-use in making more snow.

4. The method according to claim 3, wherein said feed Water as atomized by the use of pre-cooled gas under pressure.

5. A method of making artificial snow for sports use comprising (a) making artificial snow in an enclosed chamber by atomizing feed water and bringing the atomized water particles into contact with chilled air at a below-freezing temperature,

(b) passing snow from said chamber into a duct,

(c) conveying the snow through said duct by entraining it in chilled air under pressure and at a temperature below the melting point of the snow, and causing said air to move along the duct,

((1) atomizing said feed water by the use of pre-cooled gas under pressure.

6. Method of making artificial snow field for sports use comprising the following steps:

(at) making artificial snow in an enclosed chamber by atomizing feed water and bringing the atomized water particles into contact with chilled gas at a below freezing temperature,

(b) passing snow from said chamber into a duct,

() conveying the snow through said duct by entraining it in chilled gas under pressure at a temperature below the melting point of the snow, and causing said gas to move along the duct,

(d) distributing the snow from the duct to the ground at the point of use,

(e) chilling the gas in step (a) by heat exchange with a low temperature fluid in a substantially closed gas circuit including said chamber and the heat exchanger, and pumping the gas through said closed circuit,

(f) diverting a small amount of the gas from said closed circuit to said duct to provide the chilled gas for step (c).

7. The method as claimed in claim 6, including the further steps of (a) replacing said diverted gas from step (f) with atmospheric gas, 1

(b) introducing said atmospheric gas into the system in the closed snow-making chamber to remove entrained moisture from the gas.

8. Apparatus for making and distributing snow for artificial snowfields comprising:

(a) a snow-making chamber having therein means for atomizing water and means for blowing pre-chilled air countercurrent to the atomized water to.convert it into snow,

(b) valve means for conveying the snow from said chamber into a duct,

(c) means for blowing pre-chilled air through said duct to entrain the snow and to carry entrained snow along the duct to a point of use.

9. Apparatus according to claim 8, including (a) means for chilling air to a temperature well below the freezing point of water,

(b) heat exchanger means and means for passing exhaust air from said chamber, after giving up heat to the atomized water, into heat-exchange relationship, in said heat exchanger, with a refrigerating fluid at a low temperature, to re-chill said air,

(0) means for pumping said chilled air into said chamber,

(d) said means for blowing air through said duct including means for diverting some of said chilled air, at a temperature below the freezing point of water, into said duct for use in entraining and transporting said snow.

10. Apparatus according to claim 9, and means for supplying make-up air to the system including pump means for pumping atmospheric air into said chamber into contact with said pre-chilled air and with said atomized water, for removing moisture from said make-up air in said chamber.

11. Apparatus according to claim 8, including means for distributing snow from said duct onto a snowfield area to build up a layer of snow thereon for sports use, means for collecting melted snow from said snowfield as cold water, and means for returning said Water to said chamber for re-use in making snow.

12. Apparatus according to claim 8, and means for pumping Water to said chamber for atomization, and heat exchanger means for pre-cooling said water.

13. The invention according to claim 12, said last heat exchanger means including an intermediate methanol heat exchanger; means for cooling the methanol in said heat exchanger by heat exchange with a primary refrigerant at a temperature far below the freezing point of water.

14. The invention according to claim 13, said primary refrigerant being liquid natural gas (LNG), and heatexchange means utilizing said LNG for chilling the air supplied to said chamber, said LNG being also used to pre-chill the air supplied to said chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,104,920 7/1914 Osbourne 62-74 1,976,204 1/ 1932 Voorhees et a1. 62-74 2,123,878 8/1932 Brady 62-321 XR 2,676,471 12/ 1960 Pierce 6274 3,146,951 5/1963 Brown 239-399 FOREIGN PATENTS 1,129,811 1/1957 France.

ROBERT A. OLEARY, Primary Examiner. MEYER PERLIN, Examiner.

W. E. WAYNER, Assistant Examiner. 

1. METHOD OF MAKING AND DISTRIBUTING SNOW FOR SPORTS USE AT ABOVE-FREEZING TEMPERATURES, WHICH COMPRISES (A) MAKING ARTIFICIAL SNOW IN A CONTROLLED CHAMBER IN AN ATMOSPHERE MAINTAINED BELOW THE FREEZING POINT OF WATER, (B) PASSING SNOW FROM SAID CHAMBER INTO A DUCT, (C) CONVEYING THE SNOW THROUGH SAID DUCT BY ENTRAINING IT IN CHILLED AIR UNDER PRESSURE AND AT A TEMPERATURE BELOW THE MELTING POINT OF THE SNOW, AND CAUSING SAID AIR TO MOVE ALONG THE DUCT, (D) DISTRIBUTING THE SNOW FROM THE DUCT TO A REMOTE POINT OF USE. 